lab5-2 실습 시작

+export APP_NAME=hello_world
+export MOD_NAME=hooker
+
+PWD=$(shell pwd)
+APP_PATH=$(PWD)/d$(APP_NAME)
+MOD_PATH=$(PWD)/d$(MOD_NAME)
+
+all: $(MOD_NAME) $(APP_NAME)
+
+$(MOD_NAME):
+	$(MAKE) -C $(MOD_PATH)
+	mv $(MOD_PATH)/$@.ko $(PWD)
+
+$(APP_NAME):
+	$(MAKE) -C $(APP_PATH)
+	mv $(APP_PATH)/$@ $(PWD)
+
+clean:
+	$(RM) $(PWD)/$(MOD_NAME).ko
+	$(RM) $(PWD)/$(APP_NAME)
+	arm-linux-gnueabihf-gcc -C $(MOD_PATH) clean
+	arm-linux-gnueabihf-gcc -C $(APP_PATH) clean

+APP_NAME := hello_world
+
+all:
+	arm-linux-gnueabihf-gcc -o $(APP_NAME) $(APP_NAME).c
+
+clean:
+	$(RM) $(APP_NAME).o

+#include <stdio.h>
+
+int main(int argc, char *argv[]){
+	char sHelloMsg[] = {"Hello world!"};
+	printf(sHelloMsg);
+	return 0;
+}

+cmd_/root/hooking/dhooker/hooker.ko := arm-linux-gnueabihf-ld -EL -r  -T ./scripts/module-common.lds --build-id  -o /root/hooking/dhooker/hooker.ko /root/hooking/dhooker/hooker.o /root/hooking/dhooker/hooker.mod.o

+/root/hooking/dhooker/hooker.ko
+/root/hooking/dhooker/hooker.o

+obj-m := hooker.o
+
+KDIR=/root/working/linux
+PWD=$(shell pwd)
+TOOLCHAIN=arm-linux-gnueabihf-
+TARGET=arm
+
+all:
+	$(MAKE) -C $(KDIR) M=$(PWD) ARCH=$(TARGET) CROSS_COMPILE=$(TOOLCHAIN) modules
+
+clean:
+	$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) clean

+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/syscalls.h>
+#include <linux/string.h>
+
+#define SYSCALL_TABLE_BASE_ADDR (0x8000fc28)
+#define MANAGER_PERMISSION (0xff)
+
+unsigned int ** g_puSysTableAddr = (unsigned int**) SYSCALL_TABLE_BASE_ADDR;
+unsigned int g_uPrevAP = 0x00;
+unsigned int g_uNewAP = MANAGER_PERMISSION;
+unsigned int (* sys_write_orig)(int fd, char *byf, size_t count);
+
+//sys_write_orig() 호출 전 pBuF의 내용 수정
+unsigned int sys_write_hooked(int nFD, char *pBuf, size_t nCnt){
+
+	if(nFD == 1){
+		memset(pBuf, 0, nCnt);
+		strcpy(pBuf, "Hacked!!!\n");
+		return sys_write_orig(nFD,pBuf, nCnt);
+	}
+	else{
+		return sys_write_orig(nFD,pBuf, nCnt);
+	}
+
+}
+
+int __init Hook_Init(void){
+	sys_write_orig = (void *)g_puSysTableAddr[__NR_write];
+
+	__asm__ __volatile__("mrc p15, 0, %0, c3, c0" : "=r"(g_uPrevAP));
+	__asm__ __volatile__("mrc p15, 0, %0, c3, c0" : : "r"(g_uNewAP));
+	
+	g_puSysTableAddr[__NR_write] = (unsigned int *) sys_write_hooked;
+	
+	__asm__ __volatile__("mcr p15,0, %0, c3, c0" : :"r"(g_uPrevAP));
+	return 0;
+}
+
+void __exit Hook_Exit(void){
+	__asm__ __volatile__("mrc p15,0, %0, c3,c0" : "=r"(g_uPrevAP));
+	__asm__ __volatile__("mcr p15, 0, %0, c3, c0" : :"r"(g_uNewAP));
+
+	g_puSysTableAddr[__NR_write] = (unsigned int *) sys_write_orig;
+ 
+        __asm__ __volatile__("mcr p15,0, %0, c3, c0" : :"r"(g_uPrevAP));
+}
+
+module_init(Hook_Init);
+module_exit(Hook_Exit);

+#include <linux/module.h>
+#include <linux/vermagic.h>
+#include <linux/compiler.h>
+
+MODULE_INFO(vermagic, VERMAGIC_STRING);
+
+__visible struct module __this_module
+__attribute__((section(".gnu.linkonce.this_module"))) = {
+	.name = KBUILD_MODNAME,
+	.init = init_module,
+#ifdef CONFIG_MODULE_UNLOAD
+	.exit = cleanup_module,
+#endif
+	.arch = MODULE_ARCH_INIT,
+};
+
+static const struct modversion_info ____versions[]
+__used
+__attribute__((section("__versions"))) = {
+	{ 0xb344870e, __VMLINUX_SYMBOL_STR(module_layout) },
+	{ 0x2e5810c6, __VMLINUX_SYMBOL_STR(__aeabi_unwind_cpp_pr1) },
+	{ 0xfa2a45e, __VMLINUX_SYMBOL_STR(__memzero) },
+	{ 0xb1ad28e0, __VMLINUX_SYMBOL_STR(__gnu_mcount_nc) },
+};
+
+static const char __module_depends[]
+__used
+__attribute__((section(".modinfo"))) =
+"depends=";
+
+
+MODULE_INFO(srcversion, "2DEEDF502E82CB7C5A221F0");

+kernel//root/hooking/dhooker/hooker.ko